1. Field of the Invention
The present invention relates to an electromotive active dynamic vibration absorber apparatus for a vehicle, and more particularly, to an electromotive active dynamic vibration absorber apparatus for a vehicle having improved performance by disposing coil units in the up-down direction.
2. Description of Related Art
Researches and studies have been conducted to attenuate vibration, because the vibration is generated in vehicles due to operation of the engine.
Dynamic vibration absorbers are devices reducing the amplitude of vibration by intentionally producing anti-node against generated vibration and have been widely used as device for attenuating vibration of vehicles.
The dynamic vibration absorbers implement a mass-spring system. Further, in the dynamic vibration absorbers, a device that senses generated vibration and attenuates the vibration by adjusting the amplitude and cycle in accordance with the amplitude and frequency is called an active dynamic vibration absorber. The active dynamic vibration absorber includes a dynamic vibration absorber, which is a mass-spring system, and a sensor and a unit which can reciprocate the vibration absorber, using electrical energy.
Referring to FIG. 1A, vibration of an engine is transmitted to a chassis through an engine mount, such that the vehicle body entirely is vibrated. Although the vibration is attenuated at a predetermined level across the engine mount, it is not satisfactory. Therefore, an active vibration absorber apparatus is additionally installed to attenuate the vibration that is transmitted from the engine. As shown in the figure, the active vibration absorber apparatus includes, in addition to a vibration absorber, an accelerometer that senses the magnitude and direction of vibration of the chassis, a controller that senses the RPM of the engine and controls the active vibration absorber in response to a signal from the accelerometer, and an amplifier that amplifies an electric signal transmitted from the controller.
As shown at the right in the figure, the active vibration absorber apparatus having this configuration has an effect of attenuating the vibration from the chassis by controlling the vibration absorber to generate vibration having a phase opposite to the vibration that is generated from the engine and transmitted through the engine mount. Since the active vibration absorber apparatus having the configuration can generate vibration having the inverse phase in accordance with vibration differently generated in accordance with the RPM of the engine, it is possible to more effectively control the vibration of the engine even in high-speed and low-speed traveling of the vehicle.
In an active vibration absorber apparatus, a vibration absorber that includes a coil unit wound therein to vibrate in response to an electric signal and a yoke assembly moved by electric force, when electricity is generated by coils, and having a predetermined weight therein. The yoke assembly is moved in different directions by force that is continuously applied and leaf springs are fastened to the top and the bottom of the yoke to convert the movement into vibration.
FIG. 1B is a cross-sectional view showing a vibration absorber of the related art, in which leaf springs 2a, 2b are attached to a yoke assembly 3. Referring to the figure, the yoke assembly 3 having upper and lower protrusions where the leaf springs 2a, 2b are attached, and the leaf springs 2a, 2b are fastened to a housing 4 to transmit vibration. However, a coil unit 1 that vibrates the yoke assembly 3 by generating a magnetic field is disposed only at the upper potion in this structure. Therefore, the magnetic field is generated only at one side, which should be overcome.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.